1. Field of the Invention
The present invention relates to a wiring board and a method for manufacturing the wiring board, and more particularly to a wiring board incorporating a semiconductor chip and a method for manufacturing the wiring board.
2. Description of the Related Art
Nowadays, performances of electronic devices using semiconductor devices such as semiconductor chips have been progressively improved. A high density when the semiconductor chips are mounted on a board, the miniaturization of the board when the semiconductor chips are mounted and a saved space have been required.
Accordingly, a board in which semiconductor chips are embedded, what is called a chip-incorporated wiring board has been proposed and various structures for incorporating the semiconductor chips in the board have been proposed. The above-described chip-incorporated wiring board has a wiring connected to the semiconductor chips, and connecting sections are formed so that the wiring board is connected to other devices or a mother board or the like. (For example, refer to JP-A-2004-327624, JP-A-2001-352007 and JP-A-2003-142628.)
However, when the small thickness and the high density of the chip incorporated wiring board are to be realized, a problem of warpage of the wiring board sometimes arises. In order to deal with the warpage, for instance, a board having a prescribed thickness such as a core board needs to be laminated on a layer in which the semiconductor chips are embedded so as to suppress the warpage. However, in such a laminated structure, a problem arises that the small thickness and the high density of the wiring board are hardly realized.
In recent years, since the semiconductor chips operating at high speed have a large quantity of heat generation, there is a problem that the wiring board in which the semiconductor chips are incorporated may possibly generate a warpage owing to the heat generation.
As described above, it is difficult to reduce the thickness of the wiring board, while the warpage of the wiring board is suppressed. Especially, when the quantity of generated heat of the semiconductor chips is large, it is more difficult to reduce the warpage.